Solar collector fields for solar heating plants in district heating systems

Background for project:

Solar heating plants in district heating systems are installed in large numbers in Denmark. It is expected that the total solar collector area of solar heating plants in operation in Denmark will be doubled by the end of 2013, compared to the area of solar heating plants being in operation by the start of 2013.
By the end of 2013 the total collector area of all Danish solar heating plants will be about 600,000 m² and almost 1% of the heat distributed in Danish district heating networks will be solar heat. It is expected that the strong growth of installed solar heating plants will continue in the future. Denmark is a frontrunner on solar heating plants and DTU Byg is an international frontrunner on research in the field. The project will help DTU Byg to maintain this position.
Today solar collector fields are designed and controlled based on the experience of solar collector manufacturers and consultants in the solar heating field and on simple optimization tools. In order to improve the basis for design and control of optimized solar collector fields there is a need for detailed simulation models for solar collector fields which can be used to calculate the thermal performance of the solar collector fields.

Goals for project:

The aim of the project is to develop and validate detailed simulation models for differently designed and controlled solar collector fields for solar heating plants in district heating systems. Further, calculations with the developed model will elucidate how best to design and control solar collector fields for different applications.

Content of project:

The project will be focused on solar collector fields for solar heating plants in district heating systems.
Detailed simulation models for different solar collector types and differently designed and controlled solar collector fields consisting of a number of collector rows with collectors connected in series in each row will be developed and validated by means of measurements from the solar collector test facility at the Technical University of Denmark and from Danish solar heating plants.
The solar collector field can include both high and/or low efficient collectors. Both flat plate and concentrating tracking solar collectors will be considered.
Further, the flow distribution in the collector field, the shadow effects from rows, the heat loss of the pipes in the solar collector loop and the heat capacity of the solar collectors as well as the collector efficiency of different collector types for different collector tilts and different flow rates will be considered.
Calculations of the thermal performance of differently designed collector fields with different control strategies will be carried out with different weather data in order to optimize the collector field hydraulic and the control strategy for different district heating systems. Different applications for the solar collector fields will be included in the investigations.

A part of the study will be carried out at ARCON Solar A/S. ARCON Solar A/S is the world's leading manufacturer of large-scale solar thermal plants for the district heating sector and others. ARCON Solar A/S has installed more than 300,000 m² of solar collectors since 1974.